By headphones do you also include those that use the iPhone's spatial processing (with crude sensor-based HRTF) algorithms? If so, I disagree. I can't say how it stacks up against Atmos on a multispeaker setup, but it generally provides far greater soundstage and imaging on Airpods Pro than the 2-ch tracks.
As I've noted above in this thread, this is not necessarily a good thing, as it places a lot of responsibility on the mixing engineer to put things in the right place, resulting in an uncanny feeling when done improperly in a naturalistic recording. Maybe this feeling is not as strong on multichannel, but
I'm still hoping someone will take me up on listening to "The Girl from Ipanema" on "Getz/Gilberto" on a multichannel setup, and tell me if it sounds good.
For me, it's a disaster. First, Joao's vocals move from left the center-left. I assume this was done because Astrud's vocals are also left, so as to create some separation (even though they do not sing at the same time). But the problem is that Joao's guitar stays in the same place! So now he's no longer playing the guitar, or his head has left his body! Adding to that, the vocals on the original mix are pretty dry. On the Atmos mix, they are drenched in echo. It literally sounds like it's coming from a bathroom. Similarly, the effect does not extend to the guitar, which enhances the sense that Joao is not playing the guitar.